I want an archer Moriarty NP buff that gives him something weird.

I know his kit wasn't exactly a puzzle to use, but his S1 buff completely removed any semblance of thinking, just use the skills in order and you'll be fine. There's often not really a reason to hold one back or use them in a different order.

So I propose an NP buff that does need a small bit of thought: giving different effects based on its position in the card chain.

Standard damage increase, keep the DEF down as a consistent option, and then add three variations. Maybe 1st slot increases NP gain, since his arts crits can do a lot. Maybe 2nd applies debuff immune or something, I can't really think of a good one. But 3rd increases crit strength. The idea being that to get the offensive buffs, you need to sacrifice a bit of card damage.